The instant invention relates to the field of dentistry, and more particularly to an improved base structure for a dental prosthesis and to a method of installing and assembling the prosthesis in the mouth of a patient.
A variety of different types of removable and permanent dental prostheses have been heretofore available for replacing missing teeth in the mouths of patients. In this connection, conventional removable dental bridges possibly represent the most common type of heretofore available dental prosthesis, and they have been utilized for replacing missing teeth in mouths of patients for many years. Other types of heretofore-available removable dental prostheses are disclosed in the U.S. Pat. Nos. 1,685,289 to Miller; 1,702,282 Stoloff; 3,717,931 Konig; 4,302,187 Yoon; 4,345,901 Romagnoli; 4,348,181 Dawson; 4,380,434 Weissman; and 4,406,622 Yoon. More recently, however, it has been recognized that it is possible to permanently secure a dental prosthesis in the mouth of a patient to provide a permanent replacement for one or more missing teeth and that a permanent prosthesis can have significant advantages over a removable prosthesis from a practical standpoint. The device disclosed in the U.S. Pat. No. 4,163,318 to Tigani which represents the closest prior art to the instant invention of which the applicants are aware and the device disclosed in the applicants' copending U.S. pat. application Ser. No. 751,371 now U.S. Pat. No. 4,609,355 issued on 9/02/86 are generally exemplary of some of the types of permanent dental prostheses which have been heretofore known. Generally, the heretofore-known permanent dental prostheses have comprised a body portion which defines an artificial tooth or at least a base structure for an artificial tooth and a pair of pins or tabs which extend outwardly from opposite sides of the body portion and are receivable in notches or holes in the adjacent natural teeth for securing the body portion between the two natural teeth. In most cases, the pins or tabs of a prostheses of this type have beem cemented in the holes or notches in the adjacent teeth to secure the body portion of the prosthesis in position. As an alternative to this type of structure, another type of permanent dental prosthesis has recently been developed comprising anchor elements which are permanently securable to the sides of the teeth on either side of an opening or gap in the mouth of a patient and a body portion which is permanently securable to the anchor elements to secure it in the gap. In this connection, the anchor elements which are used in a prosthesis of this type are permanently securable to the adjacent teeth with pins which are cemented in small holes in the adjacent teeth. Until recently, it was not practical to secure anchor elements in this manner since it was extremely difficult to drill the proper holes with the types of dental drills which are available. However, recent improvements in dental drills have now made the use of anchor elements of this type practical. In any event, it has been found that anchor elements which are permanently secured to teeth in this manner can provide an effective and durable means of securing a dental prosthesis in the mouth of a patient. Nevertheless, although anchor elements of this type have recently been used for securing artificial teeth in the mouths of patients, they have only been used in combination with preformed artificial teeth which have not been adjustable to fit gaps of different sizes and which have therefore required substantial amounts of custom dental work in order to adapt and fit them to the mouths of patients and in order to adapt them to be secured with anchor elements.
The instant invention provides a novel and effective base structure for a dental prosthesis which is securable in the mouth of a patient with anchor elements of the above-described type but which is adjustable to adapt it to be installed in the mouth of a patient without substantial amounts of custom dental laboratory work. Specifically, the base structure for a dental prosthesis of the instant invention comprises first and second anchor elements which are securable on the sides of spaced first and second teeth and a base element which is securable to the anchor elements to retain the base element in the gap between the first and second teeth. The base element, however, comprises first and second base element portions which are received in interfitting relation and slidable in telescoping relation with respect to each other in a direction which extends between the anchor elements to enable the base element to be adjusted to fit the width of the gap. The anchor elements are preferably tapered in their outward extents away from the gum of the patient when they are mounted on their respective teeth, and the base element is configured to receive the first and second anchor elements in snug, interfitting relation when the base element is aligned with the gap and advanced toward the gum. The first and second base element portions preferably define a tooth-like configuration of slightly reduced dimension in the base element, the first base element portion preferably has an aperture therein which is disposed in a direction which extends between the anchor elements, and the second base element portion preferably comprises a pin which is slidably received in the aperture in the first base element portion to enable the first and second base element portions to be slidably adjusted in telescoping relation with respect to each other. Further, the pin in the second base element portion is preferably received in the aperture in the first base element portion so that the first and second base element portions are slightly rotatable with respect to each other to compensate for minor misalignments in the positions of the anchor elements on the adjacent teeth and in one embodiment of the base structure, a spring is provided for biasing the first and second base element portions apart.
In order to secure and form a dental prosthesis in the mouth of a patient in accordance with the method of the instant invention, first and second anchor elements are secured to spaced first and second teeth, respectively, on opposite sides of a gap in the mouth of a patient, and the base element is assembled in the gap so that it is received in interfitting relation with the anchor elements. In this regard, because the first and second base element portions are slidable with respect to each other and preferably slightly rotatable, they can easily be interfitted and assembled with the anchor elements without requiring custom dental laboratory work. After the base element has been assembled with the anchor elements in the gap in this manner, the first and second base element portions are permanently secured with respect to each other, and an outer shell or casing having a tooth-like outer configuration is formed over the base element. Thereafter, the base element with the outer casing thereon is secured to the anchor elements to provide a permanently secured prosthesis in the mouth of the patient. In the preferred application of the method, after the anchor elements have been secured on the first and second teeth in the mouth of the patient but before the base element has been assembled in the gap, a study model is made of the first and second teeth with the anchor elements thereon by conventional dental techniques. The base element is then assembled with the anchor elements in the gap and the first and second base element portions are cemented together. Thereafter, the base element is removed from the patient's mouth and placed on the study model, the outer shell is formed on the base element while it is on the study model, and finally the base element with the outer shell thereon is installed in the mouth of the patient and secured to the anchor elements with a suitable cement.
Accordingly, it is a primary object of the instant invention to provide an effective base structure for a permanent dental prosthesis.
Another object of the instant invention is to provide a dental prosthesis comprising an adjustable base element and a pair of anchor elements which are securable to a pair of spaced teeth in the mouth of a patient.
A still further object of the instant invention is to provide an improved method of forming and securing one or more artificial teeth in the mouth of a patient.